SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '496cefb01ef826d986ebcb92fd7fb92a8dd567a4c4208db784afb2c7d60d812e' 
  AND token = '3e96o656gOoqnOA702AEFDlPQeHBKCBtgsN9BcvT8F4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}